Let x represent the side length of the square end, and let d represent the dimension that is the sum of length and girth. Then the volume V is given by
V = x²(d -4x)
Volume will be maximized when the derivative of V is zero.
dV/dx = 0 = -12x² +2dx
0 = -2x(6x -d)
This has solutions
x = 0, x = d/6
a) The largest possible volume is
(d/6)²(d -4d/6) = 2(d/6)³
= 2(108 in/6)³ = 11,664 in³
b) The dimensions of the package with largest volume are
d/6 = 18 inches square by
d -4d/6 = d/3 = 36 inches long
The binomial cumulative probability with p=0.5 for 3+ successes is as follows:

for p=0.5 (50% success rate) it becomes:

the probability is 0.65625, or about 66%
(2x +3)(2x-3)= 0
x= -3/2 x = 3/2
40,023,032 = (4 x 1000000000) + (0 x 100000000) + (0 x 10000000) + (0 x 1000000) + (2 x 100000) + (3 x 10000) + (0 x 1000) + (0 x 100) + (3 x 10) + (2 x 1)